1. Field of Invention
The present invention relates to a touch control device. More particularly, the present invention relates to a touch control panel capable of withstanding ultra-violet rays.
2. Description of Related Art
Due to the persistent progress in semiconductor technologies, the level of integration of circuits and their operating speed increases at an ever-increasing rate. The modern world is filled with digital electronic products. However, before the transmission of digital data or signals required by a digital control device, an input mechanism for inputting data is necessary. Digital data is commonly input through a keyboard using a high-level language format. For example, the computer keyboard is able to input text and instructions. Nevertheless, keyboard is not the best data input method under all circumstances.
To ease digital data input and control, another common input method is a touch control panel. In a system incorporating a touch control panel, data and instructions can be fed into a system by touch. In fact, the touch control panel provides a user with a free and convenient method of input. For example, transparent touch control panel may be adhered to certain display region of a flat panel display screen. Rather than inputting data through a keyboard, data is directly fed into a system by touching the display panel. Unlike a keyboard, the touch panel is an input device that receives signals and hence may transmit pictures and textual writings. Because of such conveniences, touch control panel is also used in many electronic devices.
However, a conventional touch control panel has little resistance for the passage of ultra-violet rays. When the touch control panel is used in outdoor activities or in areas having a high ultra-violet index, the ultra-violet rays can easily penetrate into the light-channeling board or backlight panel. In general, the light-channeling board is made of polycarbonate (PC) or polymethyl methacrylate (PMMA). Since PC and PMMA may decompose in the presence energetic light rays, prolonged illumination by ultra-violet light may lead to deterioration such as the fogging of the display screen.
FIG. 1 is a schematic cross-sectional view of a conventional touch control panel 110. As shown in FIG. 1, the touch control panel 110 includes a transparent substrate 100. A transparent electrode 102 is formed over the substrate 100. In general, the transparent electrode 102 is made of an indium-tin-oxide (ITO) compound. An adhesion layer 103 is formed near the edges of the transparent electrode 102. A contact layer 104 is attached to the adhesion layers 103. At present, the contact layer 104 is mostly made from material such as polyester or glass. The contact layer 104 also has a layer of transparent electrode 102 on the side facing the transparent. substrate 100. A plurality of spacers 108 is formed in the space between the transparent substrate 100 and the contact layer 104. The spacers prevent direct contact of the transparent electrode 102 attached to the transparent substrate 100 with the transparent electrode 102 attached to the contact layer 104 due to sagging as a result of self-weight. The spacers 108 are formed over the transparent electrode 102 of the transparent substrate 100 by printing, for example. The outer surface of the contact layer 104 may further include a hard coating 106 for protecting the contact layer 104 and increasing its hardness. When the contact layer 104 is touched so that the transparent electrode 102 on the transparent substrate 100 is contacted, the position of the contact point is registered through a difference in resistive value at the point of contact.
The aforementioned touch control panel 110 has no special provision for blocking out ultra-violet light and hence ultra-violet rays will illuminate the devices underneath the panel. When the touch panel 110 and a liquid crystal display panel are used together, ultra-violet rays can still penetrate into the light-channeling panel causing the aging problem.
FIG. 3 is a schematic cross-sectional view of a conventional liquid crystal display panel with a touch panel structure therein. As shown in FIG. 3, a conventional touch control panel 110 is disposed over a display panel 206. In general, the touch control panel 110 is attached to the edges of the display panel 206 through a double-sided tape 208. The display panel 206 is a liquid crystal display panel, for example. Since a conventional touch control panel 110 has no provision for resisting ultra-violet light, ultra-violet light can easily penetrate into the light-channeling panel (not shown) inside the display panel 206. Prolonged illumination to ultra-violet light rays may lead to aging of the light-channeling panel and result in a hazy display panel.